THE STRUGGLE FOR IRAQ; BUSH DECLARES IRAN'S ARMS ROLE IN IRAQ IS CERTAIN

Published: February 15, 2007

President Bush said Wednesday that he was certain that factions within the Iranian government had supplied Shiite militants in Iraq with deadly roadside bombs that had killed American troops. But he said he did not know whether Iran's highest officials had directed the attacks.

Mr. Bush's remarks amounted to his most specific accusation to date that Iran was undermining security in Iraq. They appeared to be part of a concerted effort by the White House to present a clearer, more direct case that Iran was supplying the potent weapons -- and to push back against criticism that the intelligence used in reaching the conclusions was not credible.

Speaking at a news conference in the East Room of the White House, Mr. Bush dismissed as ''preposterous'' the contention by some skeptics that the United States was drawing unwarranted conclusions about Iran's role. He publicly endorsed assertions that had until now been presented only by anonymous military and intelligence officials, who have said that an elite branch of Iran's Islamic Revolutionary Guard Corps known as the Quds Force has provided Shiite militias in Iraq with the sophisticated weapons that have been responsible for killing at least 170 American soldiers and wounding more than 600.

''I can say with certainty that the Quds Force, a part of the Iranian government, has provided these sophisticated I.E.D.'s that have harmed our troops,'' Mr. Bush said, using the abbreviation for improvised explosive device. ''And I'd like to repeat, I do not know whether or not the Quds Force was ordered from the top echelons of the government. But my point is, what's worse, them ordering it and it happening, or them not ordering it and its happening?''

The House of Representatives is debating a resolution disapproving of Mr. Bush's plan to send more than 20,000 additional troops to Iraq. [Page A16.] And so Mr. Bush used his appearance to defend that decision as necessary in the face of deteriorating security in Baghdad. Asked about a possible American response to Iranian interference, he said, ''We will continue to protect our troops.'' With skeptics asking why the intelligence about Iran's meddling is coming to light now, a number of possibilities have been raised, including the increase in attacks and American casualties in recent months. [Page A16.]

American intelligence officials have said they think that top leaders in Iran must have approved of the attacks on the American forces, in part because the Quds Force has historically reported to the country's top religious leaders. But aides to Mr. Bush, mindful of the criticism about its use of intelligence before the Iraq war, said the White House wanted to be careful not to make that kind of accusation without hard proof.

As Mr. Bush discussed Iran in Washington, the chief American military spokesman in Baghdad provided a more detailed, on-the-record account of how the administration believed the weapons, particularly lethal explosive devices known as explosively formed penetrators, or E.F.P.'s, got to Iraq. The spokesman, Maj. Gen. William B. Caldwell IV, was also careful not to link the actions of the Quds Force directly to Iran's top leaders. He said American assertions about a link between the weapons and the force were based on information obtained from people, including Iranians, detained in Iraq in the past 60 days.

''They in fact have told us that the Quds Force provides support to extremist groups here in Iraq in the forms of both money and weaponry,'' General Caldwell said. He added: ''They have talked about how there are extremist elements that are given this material in Iran and then it is smuggled into Iraq. We have in fact stopped some at the border and discovered it there, coming from Iran into Iraq.''

The coordinated messages out of Baghdad and Washington were an effort by the White House to tamp down reports of divisions within the American government about who in Iran should be held responsible for the weapons shipments. A senior Defense analyst said at a briefing in Baghdad over the weekend that the effort was being directed ''from the highest levels of the Iranian government.'' But Gen. Peter Pace, the chairman of the Joint Chiefs of Staff, offered a contradictory account this week, telling The Associated Press that while some bomb materials were made in Iran, ''that does not translate that the Iranian government, per se, for sure, is directly involved in doing this.''

At Wednesday's news conference, Mr. Bush suggested that it did not matter whether senior leaders were involved. ''What matters is, is that we're responding,'' Mr. Bush said. He said that if the United States found either networks or individuals ''who are moving these devices into Iraq, we will deal with them.''

Some experts said the question of Iran's responsibility remained important. ''There's a big difference between saying that there is a rogue element doing things and then asking the Iranian government to rein it in, as opposed to saying this is a calculated deliberate strategy of the Iranian government,'' said Vali Nasr, a Middle East scholar at the Council on Foreign Relations. ''That has very different implications in terms of how do you hold Iran culpable.''

The administration's claims about Iran have been met with intense skepticism, from Democrats in Congress and from experts like David Kay, who led the search for illicit weapons in Iraq. Some critics have said the White House is using Iran as a scapegoat for its problems in Iraq, and some have suggested that the administration, which has been trying to pressure Iran into abandoning its nuclear program, is laying the foundation for another war.

On Wednesday, a leading contender for the Democratic nomination for president, Senator Hillary Rodham Clinton of New York, took to the Senate floor to call on Mr. Bush to seek authorization for any military action against Iran. ''We cannot and we must not allow recent history to repeat itself,'' she said.

Mr. Bush has said that he has no intention of invading Iran and that any suggestion that he was trying to provoke Iran ''is just a wrong way to characterize the commander in chief's decision to do what is necessary to protect our soldiers in harm's way.'' But experts say that the ratcheting up of accusations could provoke a confrontation. Gary Sick, an expert on Iran at Columbia University, said there was a ''danger of accidental war.'' He said, ''If anything goes wrong, if something happens, there's an unexplained explosion and we kidnap an Iranian, and the Iranians respond to that somehow, this could get out of control.''

Mr. Bush has also refused to meet with Iran's leaders, and he said Wednesday that he did not believe that it would be an effective way of persuading the Iranians to give up their nuclear goals. ''This is a world in which people say, 'Meet! Sit down and meet!' '' he said. ''And my answer is, if it yields results, that's what I'm interested in.''

Photos: President Bush left yesterday after his news conference at the White House, in which he talked about Iran and North Korea, among other topics. (Photo by Doug Mills/The New York Times)(pg. A16); (pg. A1)